Sentinel lymph node biopsy in pediatric Wilms tumor

Although the sentinel lymph node Biopsy (SLNB) is well stablished in solid tumors among adults but the experience on SLNB in pediatrics is still limited. In this article we report our experience of sentinel lymph node detection that is applied on pediatric solid renal tumors.

Twenty 1-16 year old children with non-metastatic primary Wilms tumor regarding the radiological studies were enrolled. Radio tracer injection was carried out after renal vein, artery and ureter ligation, at the time of radical nephrectomy. Sentinel node detection and sampling was performed in every location with radiotracer count of 3 times more than background. Finally lymph node sampling was completed following the standard current discipline in Wilms tumor surgery.

A single SLN was detected in 16 patients. 4 patients had more than one SLN. The most common site of SLN was inter aortocaval space. Histopathologic studies revealed tumor involvement in 3 sentinel nodes (15%). All other lymph node samples were also studied histologically and LN involvement was not detected in any of the cases with tumor free sentinel lymph node (no false negative case). Multiple LN involvement was reported in two patients with positive SLN in which, other involved lymph nodes were removed with the tumor during radical nephrectomy.

Intraoperative SLNB is a safe and feasible tool to improve the accuracy of staging in pediatric Wilms' tumor. We suggest to ligate renal artery and vein prior to radiotracer injection to diminish the background confounding effect.

Level II (development of diagnostic criteria in a consecutive series of patients and a universally applied "gold standard") TYPE OF STUDY: Study of Diagnostic Test.